1. Field of the Invention
The present invention relates to a chain and flight conveyor for use in conveying materials in the mining industry, and, in particular, to an improved design for the attachment of flights to conveyor chains.
2. Description of the Prior Art
In the process of underground mining, material is removed from a seam and transferred between machines which employ conveyors. Mined material is often transported and conveyed in shuttle cars which have a flat deck and conveyor chains which are designed specifically to load and unload the material therefrom. In most applications, the conveyor chains in the shuttle cars consist of two drive chains which are positioned on the extreme outer borders of the conveying decks of the cars. The drive chains consist of roller links, which contact the drive sprockets of the machine, and connecting links which are positioned between the roller links. In addition, the conveyor chains have flights which are fixed to the two drive chains and are positioned between the two chains. These flights are usually made of steel and can be a welded, tubular design or a solid, one piece design. The conveyor chain flights are positioned along the drive chains in a spacing designed to efficiently move material in the shuttle car. The flights are usually connected to the drive chains by inserting a male member on the ends of the flights through slots which are located in the roller links of the drive chains.
The prior designs have had disadvantages in several respects. In most previous designs, attachment and removal of the flights from the conveyor chains has been difficult, many times necessitating removal of the chain links to replace a flight. The drive chains in most prior designs must be moved from their normal operating position on the sprockets in order to connect the flights to the chains. In addition, forces experienced during the operation of a shuttle car which destroy the flights are transferred to the drive chains and often cause failures of those chains.
One prior art conveyor chain design appears in French Patent No. 665,420 issued to Naranovitch. That patent teaches of a conveyor chain in which the links include individual wheels. Certain links are designed differently and have a male extension fitting into a vertical U-shaped hinge element on the end of the flight. The attachment is secured by a pin. This patent, however, does not relate to a roller link arrangement which is driven by a drive gear. Also, the pins interconnecting the flights and the modified links are subjected to pure shear forces. Another design for a conveyor chain appears in U.S. Pat. No. 2,575,610 issued to Ball. That patent discloses parallel chains having flights with a male projection member thereof fitting into openings in predetermined chain links. This projection is slightly smaller than the opening thereby allowing for a small degree of tilt. Thus, the flight is pivotally connected to the side chains and replacement of flights requires that the chain be removed from the drive sprockets to remove a flight. Yet another design appears in U.S. Pat. No. 3,089,579 issued to Beck. The Beck patent teaches a conveyor flight with a removable, outwardly projecting male extension member which fits into openings in certain links on the chain. This extension is fastened to the flight by means of an interlocking tongue and groove mechanism fastened by bolts. As such, the flight may be removed from or attached to the conveyor chain without disturbing the chain tension or removing the entire load. However, in this apparatus the male extension member enters the conveyor chain and prohibits engagement of the conveyor drive sprocket with predetermined links along the chain.
The subject invention is directed toward an improved design for attachment of flights to a chain and flight conveyor which overcomes, among others, the above discussed problems and which provides for a more useful means of flight attachment which does not require a disruption of the conveyor chain for flight replacement and which allows all roller links to be engaged by the conveyor chain drive gears of the shuttle car. This new design enables attachment of the flights to the drive chains without repositioning the drive chains from their normal operating position. In addition, the component parts are designed so that, if a flight fails, the drive chains will not fail.